REGENXBIO has released early results from the pivotal Phase III portion of the AFFINITY DUCHENNE trial, which is testing RGX-202, an investigational gene therapy for Duchenne muscular dystrophy. Defeat Duchenne Canada is pleased to share that the results are encouraging.
RGX-202 is designed to deliver a functional version of microdystrophin, which is a shortened but more complete form of the dystrophin protein that muscles need to work properly. What makes RGX-202 distinct is that it includes an additional protein unit that is found in naturally occurring dystrophin but is absent from some other gene therapies currently in development.
The clinical trial enrolled 31 participants with Duchenne muscular dystrophy (DMD). Results revealed the gene therapy to have a safe and tolerable profile, targeting muscle cells appropriately. Overall, 93% of participants showed meaningful microdystrophin protein expression. This means the therapy appeared to be working at 12 weeks after treatment. Nine participants who had reached one full year of follow-up at the time of this update had improvements observed on standard Duchenne assessments, including timed movement tests. The therapy was also reported to be well tolerated.
As REGENXBIO stated directly: “microdystrophin expression levels were statistically significantly correlated with NSAA change from baseline” — meaning that boys who produced more of the protein also tended to show greater functional improvement, which is an important signal for researchers.
Based on these results, REGENXBIO plans to apply to the U.S. Food and Drug Administration (FDA) for approval in 2027.
Please see the Community Letter and Press Release from REGENXBIO below for more details.
What This Means for Canadians
This news does not mean Canadian families will be able to access RGX-202 soon.
The next step is applying to the FDA in the United States in 2027. Even if the FDA says yes, a separate application would need to be made to Health Canada where they will review the safety and effectiveness of the treatment.
The early results are a positive sign, and the research is moving forward. But the data so far comes from a small group of boys, and researchers will need more time and a larger group to fully understand how well the treatment works and how long the benefits last.
Families who want to learn more or ask about the trial can reach out to the REGENXBIO team via:
Want to know more about Duchenne Research?
Scientists and medical experts have been tirelessly pursuing diverse approaches to defeat Duchenne muscular dystrophy. From tackling the root cause to alleviating symptoms, the field of research is vast and promising. Explore the various strategies being developed and tested, and gain insights into the future of muscular dystrophy treatment: